I have used one road bike system (Shimano SPD-SL) and two mountain bike systems: Shimano's SPD and now Crank Brothers Candy X.
Verdict: Crank Brothers rock!
I've been reading about "egg beaters" for years, especially for cyclocross where mud clearing is a big deal. So when I saw the Candy X pedals on clearance for $30 at MEC, I figured I had nothing to lose.
Clicking in is very easy. Unlike the SPD, you don't even have to really line your cleat up with the pedal, you just slide your foot forward until it clicks in. You can click in from 4 sides, so it's never in the wrong position. Also, having the platform is a big plus - if you miss, you can still get a decent pedal stroke while you correct yourself. I found the SPDs are much less forgiving.
Despite being easy to click in and out of, the pedal feels remarkably firm once you're in. I didn't notice any shifting around, it is just solid.
- Tension is not adjustable at all... it's a giant spring. I'd imagine it will become looser with time, and I'll just have to replace the pedals if I want them tighter.
- No slot for a pedal wrench - you tighten them with an allen key, which is all well and good going in... but getting these puppies off might be tough.
I haven't yet tested the legendary mud clearing ability - that will come at Paris to Ancaster in a few weeks. But just visually you can see how mud would slide right through without causing trouble.